Decoding across sensory modalities reveals common supramodal signatures of conscious perception.

Neural activity in primary sensory regions not directly relevant to a task can predict conscious perception of near-threshold stimulation in a different sensory modality. Using magnetoencephalography and multivariate decoding analysis across tactile, visual, and auditory tasks, supramodal spatiotemporal patterns were identified that predicted conscious perception. These patterns included activity in visual cortex predicting conscious perception of auditory stimuli. The findings were replicated in a control experiment and were independent of the type of report (button press or withholding a button press). The results suggest a common signature of conscious access across sensory modalities, involving temporally late and widespread broadcasting of neural representations.

Study at a glance

Abstract

An increasing number of studies highlight common brain regions and processes in mediating conscious sensory experience. While most studies have been performed in the visual modality, it is implicitly assumed that similar processes are involved in other sensory modalities. However, the existence of supramodal neural processes related to conscious perception has not been convincingly shown so far. Here, we aim to directly address this issue by investigating whether neural correlates of conscious perception in one modality can predict conscious perception in a different modality. In two separate experiments, we presented participants with successive blocks of near-threshold tasks involving subjective reports of tactile, visual, or auditory stimuli during the same magnetoencephalography (MEG) acquisition. Using decoding analysis in the poststimulus period between sensory modalities, our first experiment uncovered supramodal spatiotemporal neural activity patterns predicting conscious perception of the feeble stimulation. Strikingly, these supramodal patterns included activity in primary sensory regions not directly relevant to the task (e.g., neural activity in visual cortex predicting conscious perception of auditory near-threshold stimulation). We carefully replicate our results in a control experiment that furthermore show that the relevant patterns are independent of the type of report (i.e., whether conscious perception was reported by pressing or withholding a button press). Using standard paradigms for probing neural correlates of conscious perception, our findings reveal a common signature of conscious access across sensory modalities and illustrate the temporally late and widespread broadcasting of neural representations, even into task-unrelated primary sensory processing regions.